Effect of Linear-Hyperbranched Amphiphilic Phosphate Esters on Collagen Fibers

Application of amphoteric polymers in the process of leather post-tanning

Abstract

With the characteristics of controllable charge and environmental friendliness, amphoteric polymers can be used in post-tanning process to solve the problems that arise during leather making and are caused by the low absorption rate of single-charge chemicals, incompatibility with new tanning methods, and complex operation process. In this review, the structure, performance, and preparation of amphoteric polymers are reported. Then, the charge change of collagen during different tanning and pH treatments is introduced. Finally, the application and development of amphoteric polymers during the post-tanning process of leather making are discussed. This review has certain guiding significance to the preparation and application of amphoteric polymers for tanning system.

Graphical abstract

A novel eco-friendly imidazole ionic liquids based amphoteric polymers for high performance fatliquoring in chromium-free tanned leather production

The potential environmental pollution of chrome tanned leather results in the development of ecological chromium-free leather tanning production in leather industry. However, with weakly positive charge, chromium-free tanned leather cannot strongly bind to anionic dyes, thus causing low quality of finished leather. Herein, p(DM-co-[DDVIM]Br)PS was synthesized by free radical polymerization method. The structure and properties of the targeted products were synthetically characterized. The results indicated that the use of p(DM-co-[DDVIM]Br)PS fatliquoring agent can not only make leather fibers become loose, but also improve the binding affinity between leather and anionic dye during the fatliquoring process. The fatliquoring agent adsorption rates and the dye absorption rate of the leather were as high as 99.26% and 99.01%, respectively; the fatliquoring and dye solutions were clear, so they can be used as clean materials in the fatliquoring process of chromium-free tanned leather. Leather treated with p(DM-co-[DDVIM]Br)PS fatliquoring agent had higher K/S value (12.80) and is softer than those treated with commercial fatliquoring agent. Consequently, this study can not only help improve the absorption rate of anionic wet finishing materials, but also reduce the pollution caused by chrome tanning agents, thus providing a new way for the cleaner production in leather industry.

Intercalation of modified zanthoxylum bungeanum maxin seed oil/ stearate in layered double hydroxide: Toward flame retardant nanocomposites

Zanthoxylum bungeanum Maxim Seed Oil (ZBMSO) is widely distributed in most parts of China, which cannot be edible and extensively consumed due to its high free fatty acids. This paper reports a rational route to utilization of ZBMSO in preparation of nanocomposites which can enhance leather flame retardancy and thermal stability. ZBMSO was synthesized through three-stage process, decoloration, acid reduction and sulfitation to prepare the modified ZBMSO fatliquoring agent (MZBMSO). Then nanocomposites based on MZBMSO and stearate-layered double hydroxide (s-LDH) were prepared via in-situ method. XRD and TEM results indicated that the MZBMSO intercalate into the galleries of s-LDH with uniform dispersion. Compared with MZBMSO, the leather treated by MZBMSO/s-LDH had a remarkable improvement on flame retardancy and superior softness which limiting oxygen index (LOI) increased from 23.6% to 28.0% and smoke density index decreased from 25 to 6.